The use of boats is a very popular recreational activity. The popularity of this recreational activity has led to a wide variety of boat designs, including by way of example, classic sailboats, boats specifically designed to improve the fishing experience, boats designed for speed and racing, and pontoon boats with a large flat deck designed to accommodate a number of individuals for socializing, eating, sunbathing, and swimming. Just as diverse as the number of boat designs is the number of options for propelling a boat through the water.
Sails capture the wind for propulsion and internal combustion engines turn one or more propellers to swiftly propel a boat through the water. Internal combustion engine configurations include outboard motors that are primarily attached to an exterior portion of a hull or transom of a boat with a propeller extending downwardly into the water for propulsion. Conversely, internal combustion engines are preferentially located within the confines of the boat where a shaft generally extends through the length of the boat's hull and exits through a watertight seal to permit connection to and rotate an external propeller to power the boat through the water. Placing an internal combustion engine inside a boat also lends to another form of boat design and propulsion possible: a jet boat that incorporates features of a water jet pump.
A jet boat is primarily propelled along the surface of a body of water such as a lake or ocean via a water jet propulsion system. Powerful motors draw in volumes of water from the lake or ocean and expel a stream of water from the stern of the boat with such extreme force that it swiftly propels the jet boat through the water. This water jet design in particular requires large volumes of water to be drawn into and expelled from a water jet. The powerful motors that are used in this configuration create a tremendous amount of suction to draw the large amounts of water into the system necessary to propel these boats at the desired operating speeds.
A jet boat of the type known in the art eliminates the presence of an external propeller, which offers a significant advantage to boaters. By reducing the risk of injury from a propeller, water jet propulsion has enabled greater human interaction with the boat and the water. This design element has made a number of smaller more unique boats possible, primarily those that can be operated by a lone operator. Many examples of these personal watercrafts exist as their popularity has expanded over past years.
For instance, personal watercraft manufacturers have adapted jet boat water jet propulsion technology into a unique boat design and application. Where a jet boat would accommodate one or typically two or more riders who enter and are seated in the jet boat, personal watercraft are smaller and more commonly designed for one operator to straddle the watercraft similar to a snowmobile or motorcycle. In another variation, the design of the Jet Ski®, as pioneered and trademarked by the Kawasaki Corporation of Japan, simulates water skiing by riders of these vehicles, primarily allowing one to stand and operate a steering handle while the water jet propels a single hull ski under the rider's feet. These unique applications of water jet technology are significant because they allow use of personal watercraft in areas where one would not typically expect to travel with a larger jet boat. This design coupled with its unique propulsion system has greatly expanded the use of personal watercraft for leisure recreational activity, water rescue activity, and for competitive sporting activities. Smaller bodies of water where boats are less common are now home to the smaller more versatile personal watercraft. Personal watercrafts because of their small size are easier to launch into shallow water than conventional boats. Personal watercrafts are typically lighter and have smaller trailers than larger-sized boats, such that it is possible for a lone user to launch a personal watercraft for a day of water recreation. Their unique propulsion system is free of externally mounted motors and propellers, thus making it easier to launch and use personal watercraft in smaller bodies of water and in shallow water. Smaller bodies of water and shallow areas do, however, present unique challenges to personal watercraft use and operation.
Smaller bodies of water and shallow areas are common places where one can find an accumulation of natural and manmade debris such as rocks, trash, dead fish, algae, and weeds. By the nature of both how the water jet propulsion system of personal watercraft operates and where users of personal watercraft choose to use these vehicles, personal watercraft are prone to problems with natural and manmade debris. The powerful motors of these vehicles have an inadvertent tendency to draw in water simultaneously with that of the debris that may consequentially harm the water jet propulsion system. Debris can enter the water inlet port of a water jet propulsion system and block or restrict the flow of water through the water jet. Any sufficient blockage of water flow can decrease performance of a water jet and may prevent it from functioning in a proper manner. Debris such as rocks can break or damage vital operable components of the water jet system which may necessitate expensive repairs. Some water jet systems are designed to use water to not only propel the watercraft, but also to divert a portion of that water stream to cool the internal combustion engine.
Internal combustion engines that are not properly cooled will accelerate the breakdown of lubricating oils and cause premature engine wear, ultimately of which may render the vehicle inoperable. In other instances, excessive debris in the water jet propulsion system could cause the engine to perform poorly and operate at higher revolutions per minute stressing the engine parts thereby greatly reducing the overall operational life of the personal watercraft.
There have been numerous attempts in the art to solve the aforementioned problems, including the attachment of a screen to the intake port that is adaptably designed to prevent the entry of debris and like matter into the jet propulsion system, notably of the type described in U.S. Pat. No. 3,040,695 entitled “Intake Strainer.” However, the nature of screen construction in and of itself may act as an impediment to water flow into water jet pump. In fact, a poorly designed screen may disrupt the laminar water flow characteristics along the boat's hull. Furthermore, a screen of this type may further create turbulent, air-entrained water mixtures that when fed into the water inlet port of the water jet pump may appreciably decrease the efficiency of the jet watercraft. Screens also have the disadvantage of becoming unduly obstructed by the presence of debris that may be inadvertently held for some time onto the surficial portion of the screen, as principally established by the powerful suction of the jet water pump.
To address the problem of clogged screens, the prior art offers numerous examples of screens with mechanical cleaning components such as that depicted in U.S. Pat. No. 3,253,567 entitled “Mechanism for Use in Conjunction with the Intake Opening of a Water Jet Propelled Vehicle.” These devices are extremely complex and the additional moving parts make them susceptible to higher requirements of service and maintenance and ultimately breakage. More modern personal watercrafts incorporate an intake guard configured with a pair of extended finned members connected to mounts that adaptably fit atop the water inlet port, generally being perceived to be less complex than the screen designs noted herein. Compared to such complex screen designs, the intake guard has a lower cost of manufacture and can be easily installed in new and existing jet watercraft. While the intake guard inherently offers these distinct design advantages, it may be ineffective as functioning as a barrier to water-borne debris, particularly moderately-sized rocks that can be semi-permanently trapped within the extended finned members, and protecting the water jet pump and associated operable components from damage.
Without attempting to modify the existing two bar screen design noted above, other attempts are documented in the art to address the nature of a clogged screen, including a manual cleaning device described in U.S. Pat. No. 5,690,520 entitled “Weed Removal Apparatus for a Jet Pump Propelled Watercraft.” This sort of manual cleaning device presents several challenges, including the requirement of transporting and stowing the device during nonuse and awkwardness of using the device to fully appreciate its stated utility. In fact, novice personal watercraft users many not recognize the appropriate time to use such a manual device, particularly during times of jet watercraft operation.
In other attempts to solve this problem, especially in areas where vine-like water weeds are present and pose a common problem, the screen may be configured to allow one to open and reach into the water inlet chamber and water jet to manually remove weeds. This type of inlet screen with opening capabilities is described in U.S. Pat. No. 4,027,617 entitled “Grating Apparatus for Protecting the Draft Port of a Water Jet Propulsion System.” This type of device is described as having a plurality of moving parts and springs that may have a tendency to prematurely wear and fail over a period of time. Another significant problem with the opening inlet screen is that it presumes weeds will enter the system and does little to prevent weeds from entering the system. Other attempts noted in the art to solve this problem have sought to block weeds from entering the water jet pump, such as the device described in U.S. Pat. No. 5,779,508, entitled “Anti-clogging Water Jet Craft,” wherein extra appendages are attached to the bottom of the watercraft to block debris and like matter. This extra appendage, however, complicates the process of launching and trailering personal watercraft and reduces the desirable attribute of operating personal watercraft in shallow water.
Further attempts are noted in the art, including the alteration of the screen as described in U.S. Pat. No. 3,147,733 entitled “Inlet Screen,” wherein the tines of the screen are attached to only one end of the screen. This design relies on the vibration of the engine and water flow under the boat's hull to cause the debris to remove itself from the inlet screen. This design lacks durability as the tines by design may unduly vibrate as a result of being attached to only one end. Also, this design does not solve the problem of solid compact debris, notably large rocks, which can enter the end of the screen where the tines are not attached.
Accordingly, there remains a need for a jet watercraft intake grill comprising solid, single piece construction, particularly of which prevents water-borne debris from entering into the water jet pump, functions without rider intervention, provides for an improved condition of laminar water flow into the water intake port of the water jet pump, permits continued operation of the jet watercraft in shallow water without undue obtrusiveness, and furthers the ease of loading and unloading the personal watercraft into a body of water.